Core B: Bioenergetics Mitochondrial dysfunction has long been a consistent observation in Parkinson's disease (PD). To understand the consequences of PD disease causing genetic mutations on the function of mitochondria the Bioenergetics Core B will provide the following analyses to the three projects in this program including: Measuring rates of respiration, oxygen consumption and ATP generation, Measuring calcium dynamics, Measuring reactive oxygen and reactive nitrogen species, measuring the activity of the electron transport chain enzymes and metabolic enzymes, and Measuring plasma versus mitochondria! membrane potential and mitochondria! membrane permeability. The Bioenergetics Core B is a shared resource of the Program. It will measure mitochondria! function, membrane permeability and membrane potential in the presence of AIMP2 and characterize mitochondria! enzymes, oxygen consumption and ATP concentrations in the conditional AIMP2 transgenic mice for Project 1. For Project 2 the Core will measure electron transport chain enzymes and metabolic enzymes and reactive oxygen and reactive nitrogen species in the various models of alpha-synuclein mediated neuronal injury. For Project 3 all measures of mitochondria! function will be conducted to characterize the LRRK2 knockout and LRRK2 transgenic mice. Thus this Core will play a central and integrated role in the investigations in the pathogenesis of PD of this Center.